UNIVERSITY  OF    CALIFORNIA    PUBLICATIONS. 

COLLEGE  OF  AGRICULTURE. 

AGRICULTURAL  EXPERIMENT  STATION 


BOVINE  TUBERCULOSIS. 


By  ARCHIBALD  R.-  WARD  and  CLARENCE  M.  HARING. 


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A  TUBERCULIN  TEST  OUTFIT. 


BULLETIN     No.     199 


(Berkeley,  Cal.,  August,  1908.) 


SACRAMENTO: 

w.  w.  shannon,     ::::::     superintendent  state  printing. 

1908. 


BENJAMIN  IDE  WHEELER,   Ph.D.,   LL.D.,  President  of  the   University. 


EXPERIMENT  STATION  STAFF. 

E.   J.   WICKSON,   M.A.,   Director  and  Horticulturist. 

E.  W.  HILGARD,  Ph.D.,  LL.D.,  Chemist. 

W.  A.  SETCHELL,   Ph.D.,  Botanist. 

ELWOOD  MEAD,  M.S.,   C.E.,  Irrigation  Engineer.      (Absent  on  leave.) 

LEROY  ANDERSON,  Ph.D.,  Dairy  Industry  and  Superintendent  University  Farm. 

M.  E.  JAFFA,  M.S.,  Nutrition  Expert,  in  charge  of  the  Poultry  Station. 

C.  W.  WOODWORTH,  M.S.,  Entomologist. 

R.  H.  LOUGHRIDGE,  Ph.D.,  Soil  Chemist  and  Physicist. 

G.   W.   SHAW,   M.A.,   Ph.D.,  Experimental  Agronomist  and  Agricultural   Technologist, 

in  charge  of  Cereal  Stations. 
GEORGE  E.  COLBY,  M.S.,   Chemist.      (Fruits,  Waters,  Insecticides.) 
RALPH  E.  SMITH,  B.S.,  Plant  Pathologist  and  Superintendent  of  Southern  California 

Pathological  Laboratory  and  Experiment  Station.      Whittier. 
A.   R.   WARD,   B.S.A.,   D.V.M.,   Veterinarian  and  Bacteriologist. 
E.  W.   MAJOR,   B.Agr.,  Animal  Industry. 
H.  M.  HALL,  M.S.,  Assistant  Botanist. 
H.  J.  QUAYLE,  A.B.,  Assistant  Entomologist.     Whittier. 
W,    T.    CLARKE,    B.S.,    Assistant    Horticulturist    and    Superintendent    of    University 

Extension  in  Agriculture. 
JOHN  S.  BURD,  B.S.,  Chemist,  in  charge  of  Fertilizer  Control. 
C.  M.  HARING,  D.V.M.,  Assistant  Veterinarian  and  Bacteriologist. 
H.   A.  HOPPER,  M.S.,  Assistant  in  Dairy  Husbandry. 

J.  H.  NORTON,  M.S.,  Assistant  Chemist  in  charge  Fertilizer  )        _._         „ 

„  (        Citrus  Experiment 

Experiments,  >• 

T.  F.  HUNT,  B.S.,  Assistant  Horticulturist,  )  Station,  Riverside. 

E.  B.  BABCOCK,  B.S.,  Assistant  Plant  Pathologist. 

E.  H.  SMITH,  M.S.,  Assistant  Plant  Pathologist. 

F.  L.  YEAW,  B.S.,  Assistant  Plant  Pathologist. 

H.  J.  RAMSEY,  M.S.,  Assistant  Plant  Pathologist, )        Southern  California  Patholog- 

C.  O.  SMITH,  M.S.,  "  "  )  ical  Laboratory.  Whittier. 
R.  E.  MANSELL,  Assistant  in  Horticulture,  in  charge  of  Central  Station  Grounds. 
RALPH  BENTON,   B.S.,   B.L.,  Assistant  in  Entomology. 

A.  J.  GAUMNITZ,  M.S.,  Assistant  in  Cereal  Investigations. 

RACHAEL  CORR,  M.A.,  Assistant  in  Cereal  Laboratory. 

HANS  C.  HOLM,  B.S.,  Assistant  in  Zymology. 

P.  L.  McCREARY,  B.S.,  Laboratory  Assistant  in  Fertilizer  Control. 

F.  E.  JOHNSON,  B.  L.,  Assistant  in  Soil  Laboratory. 

M.  E.  STOVER,  B.S.,  Assistant  in  Agricultural  Chemical  Laboratory. 

D.  R.  HOAGLAND,  A.B.,  Assistant  in  Agricultural  Chemical  Laboratory. 
CHARLES  FUCHS,  Curator  Entomological  Museum. 

P.  L.  HIBBARD,  B.S.,  Assistant  in  Fertilizer  Control  Laboratory. 

M.  E.  SHERWIN,  Field  Assistant  in  Agronomy. 

W.  H.  VOLCK,  Field  Assistant  in  Entomology.     Watsonville. 

E.  L.  MORRIS,  B.S.,  Field  Assistant  in  Entomology.     San  Jose. 
J.  S.  HUNTER,  Field  Assistant  in  Entomology.     San  Mateo. 

D.  L.  BUNNELL,  Clerk  to  the  Director. 


JOHN  TUOHY,  Patron,  )  TuJare   Substation,    Tulare. 

J.  T.  BEARSS,  Foreman,      * 


J.  W.  ROPER,  Patron, 
E.  C.  MILLER,  In  charge, 


University  Forestry  Station,  Chico. 


ROY  JONES,  Patron,  )  University  Forestry  Station,  Santa  Monica. 

N.  D.  INGHAM,  Foreman,    \ 

VINCENT     J.     HUNTLEY,     Foreman     of     California     Poultry     Experiment     Station, 
Petaluma. 

The  Station  publications  (Reports  and  Bulletins),  so  long  as  avail- 
able, will  be  sent  to  any  citizen  of  the  State  on  application. 


THE  TUBERCULOSIS  PROBLEM, 

By  A.  R.  Ward  and  C.  M.  Hari±\c. 


Bovine  tuberculosis  is  a  menace  that  no  stock  raiser  or  dairyman  can 
afford  to  ignore.  There  is  no  problem  confronting  agriculture  to-day 
of  more  fundamental  importance  than  that  constituted  by  this  disease. 

Tuberculosis  shortens  the  life  of  cows.  Exact  data  on  this  point  is  not 
available,  but  we  have  the  statement  of  an  experienced  San  Francisco 
dairyman  that  tuberculosis  shortens  the  average  productive  life  of  cows 
by  one  half.  It  unquestionably  reduces  the  efficiency  of  a  herd  as  a 
machine  for  producing  milk  from  feed.  When  its  existence  may  be 
detected,  the  market  value  of  the  animal  is  obliterated,  and  the  reputa- 
tion of  the  breeder  of  fine  stock  is  injured  by  general  knowledge  of  its 
presence  in  his  herd. 

Tuberculosis  saps  the  profits  of  the  cattle  business  by  rendering  beef 
unwholesome  for  human  food.  The  extension  of  the  practice  of  thorough 
meat-inspection  is  gradually  closing  the  avenues  for  the  profitable 
disposal  of  animals  seriously  affected  with  tuberculosis.  Contrary  to 
general  belief,  range  cattle  are  far  from  safe  from  tuberculosis.  Those 
range  herds,  recruited  from  dairies,  show  a  relatively  high  percentage 
of  tubercular  animals.  The  open  air  and  supposedly  sanitary  conditions 
on  the  range  are  of  little  avail  in  restraining  tuberculosis  in  cattle  after 
they  once  become  infected. 

The  losses  to  animal  industry  from  bovine  tuberculosis  are  not  con- 
fined to  cattle.  Many  hogs  are  fed  on  skim  milk  in  connection  with  the 
dairy  business,  and  in  the  Middle  West  hogs  '  *  follow ' '  beef  cattle.  Both 
result  in  the  dissemination  of  tuberculosis  among  hogs  to  an  alarming 
extent.  In  1905  the  United  States  Department  of  Agriculture  inspected 
25,357,425  hogs  post-mortem,  condemning  64,919  carcasses  and  142,105 
parts. 

The  importance  of  bovine  tuberculosis,  as  an  economic  problem  in 
agriculture,  has  too  frequently  been  clouded  by  a  discussion  of  its  public 
health  aspects.  The  incentive  for  combating  the  disease  has  too  often 
come  from  the  health  officer.  Many  dairymen  have  gathered  the  impres- 
sion that  the  general  acceptance  of  the  view  that  bovine  tuberculosis  is 
not  a  menace  to  public  health  would  end  their  difficulties  with  tubercu- 
losis. The  disease  will  be  with  us,  even  if  the  scientific  world  does 
finally  agree  that  the  menace  to  public  health  from  the  milk  of 
tubercular  cows  is  slight. 


222  UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION. 

There  is  no  abatement  of  the  demand  that  milk  be  produced  by 
healthy  cows.  Studies  of  the  subject  during  the  past  eight  years  have 
augmented  the  evidence  that  tuberculosis  of  cattle  is  transmissible  to 
man.  To  what  extent,  is  a  subject  of  discussion  only.  Whether  this  is 
eventually  shown  to  be  great  or  small,  we  shall  have  the  demand,  on  the 
ground  of  sentiment  at  least,  that  milk  be  produced  from  healthy  cows. 
At  the  present  moment  we  are  witnessing  a  marked  revival  of  the 
demand  that  milk  be  sold  only  from  cows  that  have  been  shown  free 
from  tuberculosis  by  the  tuberculin  test.  The  tuberculin-test  ordinances 
in  operation  are  creating  a  demand  for  healthy  cows.  One  of  the 
greatest  obstacles  to  their  success  is  the  lack  of  "tested"  cows  with 
which  to  supply  the  deficiency  brought  about  by  the  enforcement  of  the 
tuberculin  test.    This  gives  tested  cows  a  higher  market  value. 

During  the  past  four  years  we  have  made  tuberculin  tests  of  dairy 
cows  in  the  various  counties  of  the  San  Francisco  Bay  region  and  in 
the  Sacramento  and  San  Joaquin  valleys.  In  all,  1,976  tests  have  been 
made,  of  which  453  (22.9%)  showed  reactions.  Only  four  herds,  the 
largest  consisting  of  39  cows,  were  free  from  tuberculosis.  A  much 
smaller  proportion  of  isolated  cows  were  affected  than  those  in  herds. 
Of  71  animals,  isolated,  or  in  groups  of  five  or  less,  only  6  (8%)  reacted. 

A  more  accurate  statement  of  the  prevalence  of  tuberculosis,  as  shown 
by  our  experience,  would  be  one  compiled  from  results  of  the  tests  of 
whole  herds  the  first  time  that  they  had  been  tested.  In  this  case  the 
figures  show  1,022  animals  tested,  with  326  condemned  (31.9%). 
Tuberculosis  was  found  in  82%  of  the  herds  tested. 

Few  of  the  herds  were  particularly  suspected  of  harboring  tubercu- 
losis, and  most  were  tested  during  routine  inspections  under  the  auspices 
of  municipalities.  They  are  in  the  aggregate  representative  of  the  dairy 
cattle  producing  milk  for  city  trade  in  the  region  designated.  It  should 
be  emphasized  that  most  of  these  cows  were  in  dairies  supplying  market 
milk.  The  conditions  of  this  branch  of  the  dairy  business  require  that 
a  uniform  amount  of  milk  be  put  out  at  all  seasons.  This  necessitates 
the  frequent  purchase  of  fresh  cows,  with  the  consequent  increase  of 
opportunities  for  the  introduction  of  tubercular  infection. 

THE  CONTROL  OF  TUBERCULOSIS. 
Unfortunately,  but  unavoidably,  the  early  efforts  to  eradicate  bovine 
tuberculosis  were  undertaken  without  a  full  appreciation  of  the 
magnitude  of  the  problem.  It  was  thought  that  after  testing  all  of  the 
cattle  in  the  suspected  herds,  killing  a  few,  and  disinfecting  the  stable, 
the  disease  would  be  exterminated.  Many  dairymen,  without  compul- 
sion, made  honest  efforts  in  this  direction.  When  owners  began  to 
experience  great  losses  from  the  destruction  of  tubercular  animals,  the 


Bulletin  199.  BOVINE  TUBERCULOSIS.  223 

scheme  of  compulsory  testing,  with  indemnification  by  the  State,  was 
introduced.  With  the  funds  that  it  has  been  possible  to  get  from  legis- 
latures the  work  has  made  pitiful  progress  as  compared  with  the 
magnitude  of  the  task.  With  few  exceptions,  tuberculosis  has  succeeded 
in  keeping  pace  with  the  puny  efforts  directed  against  it.  At  present, 
State  effort  to  control  tuberculosis  is  largely  confined  to  those  herds 
where  the  owner  voluntarily  submits  to  the  testing  of  his  herd  and 
agrees  to  cooperate  by  taking  measures  to  keep  his  herd  clean. 

As  long  as  bovine  tuberculosis  was  considered  as  a  public  health 
problem  purely,  without  regard  to  the  financial  interests  of  dairymen, 
there  was  a  disinclination  on  the  part  of  the  owners  to  face  the  facts. 
The  increase  of  the  disease  among  the  cattle  in  this  country,  and  the 
better  knowledge  of  its  nature,  is  resulting  in  a  change  of  attitude.  The 
more  progressive  breeders  and  dairymen  are  appreciating  the  fact  that 
tuberculosis  is  an  unnecessary  and  unprofitable  adjunct  to  the  business, 
and  many  are  inquiring  about  methods  of  freeing  their  herds.  However, 
the  importance  of  controlling  this  disease  is  as  yet  inadequately  appre- 
ciated by  the  great  majority  of  the  owners  of  live  stock.  As  long  as 
the  breeders  are  content  to  ignore  the  presence  of  the  disease  and  make 
no  effort  to  combat  it  systematically,  just  so  long  will  this  plague  con- 
tinue to  thrive.  We  heartily  agree  with  Dr.  D.  E.  Salmon,  late  chief  of 
the  Bureau  of  Animal  Industry,  who  says,  "A  disease  so  widespread 
can  not  be  controlled  unless  those  most  interested  in  the  live  stock  of 
the  country  give  active  support  to  the  undertaking.  It  is,  therefore, 
wise  to  examine  the  subject  in  an  unbiased  manner ;  to  study  carefully 
the  nature  of  the  disease ;  to  learn  as  nearly  as  possible  what  the  losses 
are;  to  what  extent  these  losses  are  liable  to  increase,  and  whether 
measures  of  repression  are  or  are  not  advisable.  It  is  not  a  question 
of  sentiment,  but  one  of  fact,  and  should  be  examined  as  a  business 
proposition. ' ' 

The  possibility  of  eradicating  bovine  tuberculosis  from  herds  is  a 
fact  demonstrated  beyond  all  question.  Its  successful  accomplishment, 
however,  requires  the  thorough  mastery  of  the  principles  governing  the 
spread  of  the  disease.  We  believe  that  the  dairyman  must  obtain  this 
information  and  act  upon  it  in  the  conduct  of  his  business.  This  is 
indispensable  whether  State  aid  is  available  or  not.  To  that  end  we  have 
prepared  this  circular  to  describe  methods  which  have  been  successful 
in  eradicating  tuberculosis  from  dairy  herds. 

In  the  application  of  any  methods  for  the  eradication  or  prevention 
of  tuberculosis,  certain  important  characteristics  of  the  disease  should 
constantly  be  borne  in  mind. 

Its  Specific  Nature. — Tuberculosis  does  not  develop  spontaneously. 
The  cause  of  the  disease  is  the  bacillus  of  tuberculosis,  which  exists  only 


224  UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION. 

in  the  bodies  of  tubercular  animals  and  their  excretions,  or  in  substances 
contaminated  by  them.  In-and-inbreeding  can  not  produce  it.  Dark, 
filthy,  badly  ventilated  stables,  poor  food  and  crowded  conditions,  may 
contribute  to  its  rapid  spread  among  cattle,  but  the  disease  does  not 
originate  in  an  animal,  no  matter  how  bad  its  environments,  unless  it  is 
exposed  to  the  disease  virus. 

Its  Infectious  Nature. — Tuberculosis  is  most  'readily  communicable. 
This  point,  in  connection  with  the  first,  can  not  be  too  strongly  empha- 
sized. The  disease  results  from  the  association  of  tubercular  cattle  with 
healthy  ones,  and  under  such  conditions  will  spread  in  spite  of  every 
sanitary  precaution.  It  is  a  mistake  to  assume  that  the  disease  can  not 
thrive  and  multiply  among  dairy  cattle  kept  under  ideal  conditions. 
The  invigorating  influence  of  fresh  air  and  sunshine,  wide,  well-watered 
pastures,  well  ventilated,  ideally  constructed,  immaculately  clean  barns, 
and  abundant  and  well-balanced  rations  will  not  stop  its  spread.  It  is 
among  some  of  the  best  kept  herds  that  the  disease  has  been  found  to  be 
alarmingly  prevalent.  Contact,  direct  or  indirect,  is  the  chief  way  in 
which  the  disease  is  disseminated,  but  calves  frequently  contract  the 
disease  from  the  milk.  Calves  and  hogs  fed  on  milk  from  tubercular 
cows  soon  become  infected.  The  disease  has  become  in  the  last  few 
years  common  among  hogs,  not  only  in  California,  but  elsewhere.  Many 
things  point  to  the  fact  that  they  contract  the  disease  from  the  milk  and 
droppings  of  cattle,  and  not  from  one  another.  In  a  pig,  the  disease 
usually  develops  more  rapidly  than  in  a  calf.  Professor  Russell  of  the 
Wisconsin  Agricultural  Experiment  Station  has  pointed  out  that 
although  the  disease  is  usually  spread  from  herd  to  herd  by  the  purchase 
of  tubercular  animals  from  which  others  of  the  herd  gradually  become 
infected,  the  relative  rate  of  the  spread  of  the  disease  by  association  is 
not  as  rapid  as  the  rate  of  spread  produced  by  the  feeding  of  highly 
infected  milk  to  calves. 

Rate  of  Development. — Different  individual  animals  exhibit  the  widest 
variation  in  the  duration  of  the  disease.  In  the  majority  of  animals  the 
disease  pursues  a  leisurely  course,  consuming  years  before  causing  death. 
Others  develop  a  rapidly  fatal  type.  Its  onset  is  always  unobtrusive, 
and  its  progress  so  gradual  that  its  presence  does  not  inspire  apprehen- 
sion. Losses  are  so  evenly  distributed  in  point  of  time  that  they  do  not 
excite  serious  alarm,  as  do  other  less  destructive  diseases  of  the  pesti- 
lential type,  which  kill  many  suddenly. 

Recognition  of  Tuberculosis. — The  disease  is  manifest  after  death  by 
the  presence  of  tumor-like  nodules  (tubercles)  in  various  parts  of  the 
body.    These  tubercular  masses  of  Long  standing  undergo  changes  result- 


Bulletin  199.  BOVINE  TUBERCULOSIS.  225 

ing  in  the  formation  of  purulent,  or  cheesy  material,  sometimes  per- 
meated with  gritty  particles  of  lime. 

The  presence  of  the  disease  is  seldom  manifest  until  the  development 
of  the  tubercles  is  so  great  that  their  presence  interferes  with  the  duty 
of  some  vital  organ.  Rough,  hard  skin,  staring  coat,  emaciation,  chronic 
bloating,  roached  back,  and  drooping  head  only  appear  in  acute  or 
very  advanced  cases.  Coughing  is  not  necessarily  an  indication.  This 
symptom  is  usually  absent  even  when  the  disease  is  in  an  advanced 
stage,  and,  on  the  other  hand,  non-tubercular  animals  occasionally  are 
troubled  by  a  constant  cough.  Animals  in  prime  condition  may  be  badly 
infected,  and  be  quite  as  dangerous  in  spreading  the  disease  as  those 
which  show  the  symptoms.  A  very  small  percentage  of  the  seriously 
diseased  animals  can  be  detected  by  a  recognition  of  symptoms.  In 
testing  a  group  of  about  380  cows,  we  condemned  64  as  tubercular,  on 
the  basis  of  the  tuberculin  test.  Only  9  showed  physical  signs  of  tubercu- 
losis. This  observation  emphasizes  the  fact  that  a  physical  examination 
is  useless  in  recognizing  any  considerable  percentage  of  the  tubercular 
animals  in  a  herd. 

Substantial  progress  in  the  control  of  tuberculosis  depends  upon  our 
ability  to  unerringly  ascertain  the  existence  of  any  stage  of  the  disease 
in  an  individual,  as  a  guide  to  measures  for  the  prevention  of  its  spread. 
The  tuberculin  test  does  this,  and  its  discovery  opened  the  way  to  the 
successful  control  of  tuberculosis.  It  is  a  regrettable  fact  that  the 
phrase  "tuberculin  test"  in  the  minds  of  dairymen  stands  for  various 
systems  of  compulsory  slaughter  of  cattle,  and  that  it  is  not  esteemed 
as  a  discovery  of  inestimable  value  to  the  dairy  industry.  Its  compul- 
sory use,  accompanied  by  wholesale  slaughter  of  animals,  has  given 
origin  to  a  host  of  misconceptions  and  misrepresentations  regarding  its 
accuracy  that  will  hardly  be  lived  down  in  a  generation.  In  answer 
to  various  criticisms,  Dr.  D.  E.  Salmon  has  summed  up  the  accuracy 
and  safety  of  the  tuberculin  test  as  follows : 

From  the  investigations  and  observations  that  have  been  mentioned,  it  may  be 
safely  concluded — 

(1)  That  the  tuberculin  test  is  a  wonderfully  accurate  method  of  determining  if 
an  animal  is  affected  with  tuberculosis. 

(2)  That  by  the  use  of  tuberculin,  the  animals  diseased  with  tuberculosis  may 
be  detected  and  removed  from  the  herd,  thereby  eradicating-  the  disease. 

(3)  That  tuberculin  has  no  injurious  effect  upon  healthy  cattle. 

(4)  That  the  comparatively  small  number  of  cattle  which  have  aborted,  suffered 
in  health,  or  fallen  off  in  condition  after  the  tuberculin  test,  were  either  diseased 
before  the  test  was  made  or  were  affected  by  some  cause  other  than  the  tuberculin. 

The  test  is  simple  in  its  application.  It  consists  in  taking  the  tempera- 
ture of  the  animal  with  an  ordinary  clinical  thermometer  several  times 


226  UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION. 

to  determine  its  normal,  injecting  the  tuberculin*  with  a  hypodermic 
syringe,  and  then  taking  the  temperature  at  intervals  of  two  hours 
between  the  eighth  and  eighteenth  hours  after  the  injection.  Any  one 
with  intelligence  enough  to  run  a  dairy  profitably  should  be  able  to 
perform  the  labor  of  the  test  in  a  competent  manner.  The  animals 
should  be  kept  under  favorable  conditions,  and  care  needs  to  be  taken 
to  record  accurate  temperature  readings.  In  interpreting  the  tempera- 
ture records  a  careful  consideration  of  the  conditions  under  which  the 
test  is  made  and  a  knowledge  of  the  sources  of  error  is  necessary. 

Tests  by  the  Owner. — The  work  necessarily  has  been  and  must  be 
carried  on  by  those  having  some  knowledge  of  veterinary  science.  How- 
ever, we  do  not  go  to  the  extreme  of  insisting  that  the  persons  performing 
certain  details  of  the  test  shall  be  trained  veterinarians.  Any  intelligent 
dairyman  who  will  make  a  little  effort  to  familiarize  himself  with  the 
test  and  its  limitations  can  use  it  on  his  own  cattle  with  good  results. 
It  is  only  through  the  cooperation  of  breeders,  dairymen,  and  veterina- 
rians that  there  is  hope  of  immediately  improving  the  extremely  undesir- 
able conditions  which  at  present  exist.  When  the  majority  of  the 
dairymen  understand  the  use  of  the  test  and  the  importance  of  isolating 
diseased  animals,  there  will  be  far  better  prospects  of  eradicating  the 
disease  than  if  skilled  veterinarians  are  considered  indispensable.  The 
expense  of  employing  a  professional  to  perform  every  detail  of  the  test, 
is  not  only  often  prohibitive,  but  in  many  localities  no  qualified  licensed 
practitioner  is  available. 

The  Agricultural  Experiment  Station  of  the  University  of  California 
offers  to  any  dairyman  of  the  State  who  will  avail  himself  of  it  the 
opportunity  of  learning  and  perfecting  himself  in  details  of  using  the 
tuberculin  test.  Not  only  can  information  be  obtained,  but  under  con- 
ditions to  be  personally  arranged  between  the  inquiring  dairyman  and 
the  veterinarians  of  this  station,  it  will  undertake  to  supply  free  tuber- 
culin and  give  direct  assistance  in  interpreting  the  temperature  records. 

THE  TESTING  OUTFIT. 
Tuberculin. — Request  for  University  of  California  tuberculin  should 
be  addressed  to  the  Director  of  the  Agricultural  Experiment  Station, 

*  Tuberculin  is  prepared  from  glycerinated  bouillon  in  which  tubercle  bacilli 
have  been  grown  from  six  to  eight  weeks.  The  bouillon  culture  is  first  boiled  for 
two  hours  to  kill  all  the  living  organisms.  It  is  then  filtered  under  pressure  through 
a  germ-proof  earthenware  filter  to  remove  the  dead  bodies  of  the  germs,  concentrated 
by  evaporation,  a  little  carbolic  acid  added,  and  it  is  then  bottled  for  distribution. 
Its  injection  into  cattle  affected  with  tuberculosis  is  followed  in  from  ten  to  sixteen 
hours  by  a  rise  of  temperature,  which  lasts  several  hours,  and  gradually  declines  to 
normal.  We  can  find  no  evidence  that  it  causes  an  increase  in  the  rapidity  of  the 
progress  of  the  disease  in  animals  already  affected  with  tuberculosis,  or  that  it  is 
injurious  to  them  in  any  other  way.  It  does  not  even  temporarily  injure  the  quality 
of  the  milk. 


Bulletin  199.  BOVINE  TUBERCULOSIS.  227 

Berkeley.  California,  on  the  form  appearing  on  the  last  page  of  this 
bulletin. 

The  United  States  Department  of  Agriculture  also  furnishes  tubercu- 
lin free  to  health  officials.  Application  for  this  should  be  made  through 
Dr.  Charles  Keane,  State  Veterinarian,  Sacramento,  California. 

The  following  firms  sell  tuberculin  ready  for  use,  together  with  clinical 
thermometers  and  hypodermic  syringes.  Their  goods  may  also  be 
obtained  through  druggists : 

Bischoff  &  Co.,  451  Washington  street,  New  York. 

The  Cutter  Laboratory,  Berkeley,  California. 

H.  K.  Mulford  Co.,  412  South  Thirteenth  street,  Philadelphia. 

Parke,  Davis  &  Co.,  Detroit,  Michigan. 

Pasteur  Vaccine  Co.,  323-325  Dearborn  street,  Chicago. 

Syringe. — A  veterinary  hypodermic  syringe  of  at  least  6  cc.  capacity, 
such  as  is  commonly  used  to  inject  liquid  vaccine,  is  necessary.  The 
same  should  be  provided  with  a  number  of  short,  stout  needles,  well 
reinforced  at  the  base. 

Thermometer. — At  least  two  fever  thermometers  will  be  needed,  and 
where  more  than  five  animals  are  to  be  tested  a  larger  number  should  be 
provided.  Guaranteed  clinical  thermometers  can  be  purchased  at  any 
drug  store.  A  string  should  be  tied  around  the  thermometer  and 
fastened  by  a  rubber  band.  At  the  other  end  of  this  string  should  be 
attached  a  small  bulldog  clamp  or  wire  hook.  After  inserting  the 
thermometer  in  the  rectum  the  clamp  is  fastened  to  the  long  hairs  at 
the  base  of  the  tail  so  that  if  the  thermometer  is  thrown  out  it  will 
not  be  broken  by  dropping  to  the  ground.  Thermometers,  especially 
for  veterinary  purposes,  made  of  thicker  glass  and  with  a  ring  in  the 
end  are  convenient. 

Disinfectant. — A  small  bottle  of  strong  (95%)  carbolic  acid  to  be 
used  in  disinfecting  the  syringe  before  beginning  the  test,  and  to  disin- 
fect the  needle  point  before  injecting  each  animal,  is  essential. 

Vaseline. — Its  use  is  desirable  to  facilitate  inserting  the  thermometer, 
although  lard  may  be  substituted.  Between  the  times  of  taking  tempera- 
tures the  vaseline  jar  is  a  safe  and  convenient  place  to  keep  the 
thermometer. 

Ordinary  Green  Paint. — This  color  is  convenient  for  temporarily 
identifying  animals  by  numbers  placed  on  the  rump.  If  it  is  desirable 
to  mark  them  so  that  the  numbers  will  not  become  erased  for  a  week  or 
more,  rub  the  paint  well  into  the  hair  and  it  will  have  a  slight  blistering 
effect  which  will  cause  the  hair  to  stand  up  for  ten  days  or  so. 


228 


UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION. 


DIRECTIONS  FOR  MAKING  THE  TUBERCULIN  TEST. 

Identify  the  Animals. — Number  them  with  paint  or  otherwise.  It  is 
not  advisable  for  the  beginner  to  attempt  to  test  more  than  one  string 
(30  animals)   at  one  time. 

Taking  the  Normal  Temperatures. — A  convenient  way  is  to  take  two 
temperatures,  one  at  the  morning  milking  and  one  in  the  evening,  but 
it  is  preferable  to  take  two  more  at  two-hour  intervals  from  the  others. 
The  last  one  may  just  precede  the  injection  of  the  tuberculin.  Familiar- 
ize yourself  with  the  reading  of  the  clinical  thermometer,  and  if  trouble 
is  experienced,  ask  your  druggist  or  doctor  to  show  you  how.  The 
largest  intervals  on  the  scale  are  degrees,  of  which  every  second  one 
only  is  numbered.  The  smaller  intervals  designate  2-10  of  a  degree. 
Readings  can  be  made  accurately  to  half  of  one  of  these  smallest  divi- 
sions (1-10).    Insert  the  thermometer  full  length  in  the  rectum     Smear 

the  bulb  of  the  instrument 
and  the  end  of  the  index 
finger  with  vaseline  to 
facilitate  the  operation. 
Attach  the  thermometer  to 
the  base  of  the  tail  by 
means  of  the  snap,  or  a 
wire  hook  and  rubber  band, 
and  allow  the  thermometer 
to  remain  in  the  rectum 
three  minutes.  By  the  use 
of  this  device  three  or  four 
thermometers  may  be  used, 
and  the  temperature  of 
several  animals  taken  in  the  time  that  is  required  to  take  one.  Be 
sure  and  shake  down  the  mercury  below  99°  F.  each  time  before 
inserting  the  thermometer  in  an  animal. 

Temperature  of  Cattle. — The  usual  normal  temperature  of  a  milk 
cow  varies  between  101°  F.  and  103°  F.,  but  it  is  not  uncommon  to  find 
apparently  healthy  cows  that  temporarily  are  even  lower  or  higher 
than  these  limits.  Excitement  may  cause  a  temporary  rise,  excessive 
summer  heat  also  increases  the  normal  temperature,  while  the  drinking 
of  cold  water  may  reduce  the  temperature  a  degree  or  two.  Most  cattle 
are  at  their  lowest  early  in  the  morning  and  highest  in  the  afternoon. 
After  exposure  to  a  storm  or  during  the  severe  north  winds  which 
sometimes  occur  in  central  California,  the  temperature  of  the  cattle 
is  Frequently  quite  high.  The  temperature  of  calves  under  four  months 
old  is  much  more  variable  than  that  of  older  cattle. 


Fig.   2.     Manner  of  taking  the  temperature. 


Bulletin  199. 


BOVINE    TUBERCULOSIS. 


229 


Treatment  of  Animals  During  the  Test. — On  account  of  the  ease 
with  which  variations  in  temperatures  are  caused,  it  is  important  to 
keep  the  animals,  that  are  being  tested,  under  normal  conditions.  They 
should  be  fed,  watered,  and  milked  as  usual.  Avoid  as  much  as  possible 
the  violent  handling  of  nervous  cows  in  taking  their  temperatures. 

Animals  That  Should  Not  Be  Tested. — Cattle  suffering  from  any 
disease  causing  a  fever  (garget,  "fox-tail  abscess,"  retained  afterbirth, 
etc.)  should  not  be  tested  until  the  fever  has  subsided.  If  the  cattle 
have  been  recently  injected  with  tuberculin,  a  re-test  within  one  month 
will  be  unreliable,  and  it  is  safer  to  allow  six  or  eight  weeks  to  elapse. 
Most  authorities  state  that  the  test  should  not  be  applied  to  cows  within 


Fig.    3.      Manner  of  injecting  tuberculin. 

four  days  of  calving,  or  during  the  period  of  heat,  for  fear  that  these 
conditions  might  cause  a  rise.  It  is  the  usual  practice  to  inject  all 
animals,  and  take  the  above  mentioned  conditions  into  consideration, 
and  re-test  if  a  rise  in  the  temperature  does  occur. 

Making  the  Injection. — This  is  preferably  done  in  the  evening,  eight 
hours  before  the  time  of  milking  in  the  morning.  The  syringe  should 
be  disinfected  by  drawing  it  full  of  carbolic  acid,  emptying  it.  and  then 
rinsing  in  boiled  water  before  beginning  the  test.  In  addition  to  this, 
just  before  injecting  each  animal,  dip  the  tip  of  the  syringe  in  strong 
carbolic  acid  to  disinfect  it.  Fill  the  syringe  through  the  needle  from 
the  bottle  of  tuberculin,  and  avoid  contaminating  it  with  dirt.  Set  the 
burr  on  the  piston  rod  of  the  syringe  so  that  not  more  than  the  dose 


230  UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION. 

intended  can  be  injected.  The  large  numbered  divisions  on  the  syringe 
piston  rod  stand  for  cubic  centimeters  (cc).  The  size  of  dose  will  be 
stated  on  the  tuberculin  bottle.  The  injection  is  usually  made  in  the 
side  of  the  neck  where  the  skin  is  thin  and  loose.  A  fold  of  the  skin 
is  taken  in  the  left  hand,  and  the  syringe  point  inserted  in  the  pocket 
thus  formed  and  the  dose  injected.  When  a  cow  is  restrained  in  a 
stanchion  the  position  of  the  operator  shown  in  figure  3  insures  the 
greatest  security  from  interference  or  injury  by  the  movements  of 
the  cow. 

Temperature  After  Injection. — Take  temperatures  at  about  the  8th, 
10th,  12th,  14th,  16th,  and  18th  hours  after  injecting,  and  continue  in 
those  cases  showing  a  rising  temperature.  Where  an  animal  shows  a 
rise  above  102.5°  F.,  it  is  well  to  take  the  temperatures  at  more  frequent 
intervals.  In  hot  weather  it  is  essential  that  the  injection  be  timed  so 
that  the  8th  to  16th  hours  will  occur  in  the  cool  part  of  the  day. 

Interpretation  of  the  Temperature  Records. — When  the  tuberculin 
is  furnished  by  this  station  the  temperature  record  sheets  may  be 
returned  as  soon  as  the  test  is  completed,  and  an  interpretation  of  the 
results  will  be  made.  In  case  of  a  reaction  (indicating  the  presence  of 
tuberculosis)  there  must  be  a  rise  of  1.5°  F.  or  more  above  the  normal 
temperature  as  determined  on  the  preceding  day.  The  interpretation 
of  the  temperature  record  of  the  animals  showing  a  rise  of  less  than 
2°  F.  requires  care.  The  elevation  of  temperature  usually  comes  on 
gradually,  although  in  the  more  pronounced  reactions,  where  the  tem- 
perature goes  above  105.5°  F.,  the  rise  is  frequently  abrupt.  This 
should  usually  occur  between  the  8th  and  the  16th  hours.  It  should 
remain  practically  at  a  maximum  for  two  hours  or  more  and  gradually 
subside.  When  the  temperature  reaches  104°  F.  or  more,  and  is  main- 
tained for  some  hours,  the  animal  is  certainly  regarded  as  tubercular, 
if  no  fever  was  shown  before  the  injection.  Erratic  elevations  of  short 
duration  do  not  indicate  a  reaction.  The  slight  variations  caused  by 
the  weather,  the  drinking  of  cold  water,  or  the  irregular  handling  in 
applying  the  test  are  as  apparent  in  the  temperature  records  of  the 
non-reacting  cows  as  in  the  others,  and  a  comparison  of  the  tempera- 
tures of  the  animals  which  show  no  indication  of  a  reaction  should  be 
taken  into  account  in  interpreting  the  records.  In  case  of  doubt,  the 
animal  should  be  separated  from  the  herd  and  re-tested  not  sooner 
than  a  month. 

If  all  conditions  pertaining  to  the  protection  of  the  animal  have  been 
fulfilled,  the  temperature  behavior  mentioned  is  a  very  sure  indication 
that  the  animal  is  suffering  from  an  active,  although  possibly  a  very 
small  tubercular  growth.  If  there  is  no  reaction,  the  correct  interpre- 
tation is  more  difficult.     Dr.   V.  A.   Moore,   of  the  New  York  State 


Bulletin  199.  BOVINE  TUBERCULOSIS.  231 

Veterinary  College,  says  that  in  this  case  there  are  three  conditions 
which  must  be  taken  into  account,  viz. : 

(1)  If  the  animal  is  extensively  diseased  it  may,  in  rare  instances,  not  react.  In 
this  case  the  physical  condition  would  show  that  the  animal  was  at  least  not  healthy. 

(2)  If  the  test  was  made  during  the  period  of  incubation  there  would  be  no 
reaction,  although  the  disease  may  soon  develop.  (By  a  period  of  incubation  we 
mean  the  time  elapsing  between  the  exposure  to  a  disease  and  its  actual  development. 
In  tuberculosis  this  period  is  very  variable.  In  some  cases  the  disease  begins  to 
progress  at  the  day  of  infection  ;  in  others,  the  germs  may  be  lodged  for  a  long 
time  before  the  disease  actually  develops.) 

(3)  It  is  known  that  cows  which  have  reacted,  may,  because  of  the  natural 
arrest  of  the  disease,  fail  to  react  subsequently  ;  but  later  the  disease  would  start  up 
again,  when  the  animal  would  react.  Great  care  must  be  exercised,  therefore,  in 
the  interpretation  of  negative  results,  especially  tests  made  in  herds  where  tubercu- 
losis exists,  and  where  it  is  possible  that  the  animals  failing  to  react  have  been 
infected. 

Re-testing. — A  single  test  of  a  diseased  herd  can  not  be  depended 
upon  to  detect  every  tuberculous  animal.  If  any  animals  are  found 
by  the  first  test  to  be  affected,  the  herd  should  be  tested  regularly  every 
six  months.  On  account  of  the  many  chances  for  the  infection  of  a 
herd  the  practice  of  systematic  annual  testing  is  recommended  for  all 
dairy  herds.  Animals  purchased  subject  to  the  test  should  be  re-tested 
in  four  or  six  months.  As  has  already  been  mentioned,  a  re-test  within 
a  month  is  unreliable,  and  when  animals  are  re-tested  within  six  months 
it  is  better  to  use  a  double  dose  (4  cc.)  of  tuberculin. 

Proving  the  Test. — The  one  reliable  means  of  ascertaining  the 
accuracy  of  the  tuberculin  test  is  the  slaughter  of  the  animal,  and  the 
demonstration  of  the  existence  of  the  disease  in  the  organs.  This, 
necessarily,  demands  the  services  of  a  skilled  professional  man  familiar 
with  the  manifestations  of  the  disease,  and  with  the  regions  in  which 
such  manifestations  may  be  located.  In  some  cases  animals,  not  react- 
ing to  the  test,  have  been  slaughtered  on  account  of  serious  lung  disease 
with  a  view  to  determine  if  the  test  had  missed  a  tubercular  animal. 
The  manifestations  of  actinomycosis  (lumpy  jaw)  in  the  lungs  have 
been  mistaken  for  tuberculosis  in  such  instances. 

There  is  prevalent  a  popular  notion  that  the  failure  of  an  animal 
to  react  to  the  test  a  second  time  constitutes  a  demonstration  of  the 
inaccuracy  of  the  test.  The  falsity  of  this  becomes  evident,  upon  con- 
sideration of  the  facts  regarding  the  result  of  previous  injection  of 
tuberculin,  and  of  the  fact  that  recovery  may  have  occurred  in  the 
mean  time. 

Conversely,  criticism  of  the  test  and  of  the  honesty  and  skill  of  the 
man  applying  it,  has  resulted  from  the  observation  of  cases  in  which 
cattle  have  failed  to  react  once,  and  then  reacted  later  without  further 
exposure  to  infection.  The  matter  is  explained  by  the  fact  that  cows 
may  not  develop  the  disease  for  months  after  exposure  to  the  germs 


232  UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION. 

of  the  disease;  or  an  old  center  of  disease,  so  nearly  healed  that  it 
would  not  give  a  reaction  on  the  first  test,  may  later  have  become  anew 
the  center  of  active  disease. 

HOW  A  DISEASED  HERD  CAN  AT  SMALL  EXPENSE  BE  CHANGED 
TO  A  HEALTHY  ONE. 

First,  test  the  entire  herd.  Successful  methods  of  eradication  are  all 
based  on  the  intelligent  use  of  the  tuberculin  test.  After  testing,  the 
question  arises,  ' '  What  can  be  done  with  reacting  animals  ? "  Of  course 
the  reacting  animals  must  be  at  once  separated  from  the  healthy  in 
order  to  stop  the  spread  of  the  disease. 

If  the  Tuberculin  Test  Shows  Comparatively  Few  Affected. — In  this 
case,  segregate  the  reacting  animals  at  once.  It  is  unquestionably  good 
policy  to  exterminate  the  disease  by  removing  the  infected  animals 
from  the  herd,  with  a  view  of  disposing  of  the  same  as  soon  as  circum- 
stances permit.  The  method  formerly  and  most  commonly  employed 
of  disposing  of  reacting  animals  was  by  slaughter  and  burial.  Where 
this  wasteful  method  has  been  employed  the  results  have  been  dis- 
couraging; even  when  the  State  recompensed  the  owner  in  part  for 
the  loss  of  his  stock,  it  has  been  unsatisfactory.  A  large  number  of 
reacting  animals  are  usually  but  slightly  diseased.  They  readily  take 
on  flesh,  and  can  be  fattened  and  used  for  beef.  They  must  be  carefully 
examined  by  a  veterinarian  when  killed,  and  if  the  disease  is  found 
to  be  extensive,  the  carcass  must  be  condemned.  The  government  meat 
inspection  regulations  admit  the  use  of  meat  of  slightly  tuberculous 
animals  for  food,  for  it  is  recognized  that  under  such  circumstances 
the  cooking  of  meat  is  an  effective  safeguard  against  danger.  The 
University  practices  what  it  preaches  in  this  regard.  The  zeal  of 
various  health  officials  in  demanding  the  waste  of  the  flesh  of  every 
reacting  animal  has  been  a  great  setback  to  the  control  of  tuberculosis 
through  developing  opposition. 

The  Stable  Must  Be  Thoroughly  Disinfected. — A  circular  giving 
directions  for  the  disinfection  of  stables  may  be  obtained  by  addressing 
a  postal  card  request  to  the  Director  of  the  Agricultural  Experiment 
Station,  Berkeley,  Cal.  Many  of  the  failures  to  eradicate  tuberculosis 
by  the  repeated  application  of  the  tuberculin  test,  and  the  prompt 
removal  of  all  reacting  animals,  are  due  to  the  fact  that  the  stables 
and  sheds  were  not  disinfected.  The  watering  troughs  should,  of  course, 
be  disinfected.  That  bacilli  discharged  from  the  tubercular  animals 
in  the  corrals  may  remain  virulent  for  a  considerable  time  is  possible, 
although  the  action  of  direct  sunshine  quickly  destroys  them.  The 
corrals  should,  therefore,  be  thoroughly  cleaned  of  manure. 


Bulletin  199.  BOVINE  TUBERCULOSIS.  233 

If  a  Large  Proportion  of  the  Herd  Is  Found  to  Be  Diseased. — In  this 
case  if  the  reacting  animals  are  valuable  breeders,  they  may  be  isolated 
and  kept  for  breeding  purposes  by  removing  the  calves  at  once  and 
feeding  them  on  milk  of  healthy  cows,  or  on  the  sterilized  milk  of  their 
mothers.  This  is  called  the  Bang  method,  a  procedure  devised  by  Pro- 
fessor B.  Bang,  of  the  Copenhagen  Veterinary  College.  The  method  is 
as  follows : 

(1)  Test  every  animal  in  the  herd  with  tuberculin. 

(2)  Remove  the  reacting  animals,  and  keep  them  isolated  so  that  the  disease 
can  not  be  transmitted  to  the  healthy  animals,  either  by  contact,  by  the  attendants, 
or  by  the  same  feeding  or  drinking  utensils. 

(3)  Disinfect  the  stables  to  prevent  transmission  of  the  germs  left  by  the  infected 
animals. 

(4)  Test  the  healthy  herd  with  tuberculin  regularly  to  detect  any  cases  that  may 
develop  and  remove  such  animals  before  they  spread  the  disease.     Disinfect  again. 

(5)  Remove  the  calves  from  the  diseased  herd  at  birth  and  feed  them  milk  from 
the  healthy  cows,  or  milk  from  the  diseased  cows  which  has  been  thoroughly  pasteur- 
ized (heated  to  185°  F.). 

As  the  sound  herd  is  replenished,  the  isolated  cattle  may,  if  desired, 
be  fattened  and  killed,  under  proper  inspection,  for  beef. 

Bang's  method,  as  carried  on  in  Denmark,  proves  that  the  disease 
can  be  weeded  out  in  a  practical  manner.  But  in  many  of  the  herds 
in  which  the  method  was  tried,  a  varying  number  of  animals  were  found 
that  afterward  reacted  positively  to  subsequent  tests.  These  partial 
failures,  amounting  in  all  to  about  12%,  he  attributes  to  carelessness 
in  maintaining  complete  separation  of  reacting  herds  from  healthy  ones, 
and  incomplete  disinfection.  The  method  has  been  followed  by  good 
results  in  Norway  and  Sweden,  and  also  in  Hungary.  The  reports 
show  that  many  highly  infected  herds  have  been  absolutely  freed  from 
the  disease  in  four  to  six  years.  Several  experiment  stations  have 
applied  the  Bang  method  in  this  country.  Professor  Russell,  of  "Wis- 
consin, has  been  especially  successful.  The  New  York  Agricultural 
Experiment  Station,  Geneva,  N.  Y.,  has  issued  a  bulletin  reporting 
complete  success  in  the  eradication  of  tuberculosis  from  the  station 
herd.  The  method  offers  a  remedy  which  safeguards  health,  while 
giving  the  stockman  a  chance  to  perpetuate  valuable  strains  of  blood 
and  mitigate  his  financial  loss. 

The  problem  of  obviating  the  transmission  of  infection  from  the 
reacting  herd  to  the  healthy  is  very  important.  The  two  herds  must 
not  be  permitted  to  mingle  in  any  way  while  at  pasture  or  elsewhere. 
A  partition  in  the  stable  and  new  fencing  are  the  chief  features  in 
accomplishing  the  separation.  Instances  have  been  reported  where  the 
disease  has  been  apparently  transmitted  to  cattle  in  adjoining  pastures. 
It  is  possible  that  this  was  done  by  the  cows  licking  one  another  across 
the  fence.  When  applying  the  Bang  system  the  same  drinking  trough 
must  not  be  used  for  the  two  herds,  even  when  it  is  divided  by  a  parti- 


234  UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION. 

tion.  In  highly  infected  herds  the  possibility  of  a  continuation  of  infec- 
tion in  stables,  corrals,  and  pastures,  after  all  the  reacting  animals  have 
been  removed,  is  relatively  greater  than  when  only  a  few  have  been 
diseased.  This  is  especially  marked  in  stables  that  have  been  in  con- 
stant use  for  a  number  of  years.  Where  new  buildings  are  erected  in 
introducing  the  system,  it  is  advisable  to  place  the  non-reacting  animals 
there  rather  than  the  reacting  ones.  Remove  the  healthy  from  the 
diseased,  rather  than  the  diseased  from  the  healthy. 

PREVENTION  OF  TUBERCULOSIS. 

Those  dairymen  who  have  been  doing  business  in  a  small  way.  and 
have  infrequently  or  never  purchased  animals,  may  have  herds  free 
from  tuberculosis.  The  trouble  of  making  a  test  is  so  slight  that  one 
should  never  neglect  ascertaining  the  facts.  Early  discovery  will 
enable  the  owner  to  forestall  serious  trouble  later.  In  purchasing 
cattle  a  man  can  not  assume  that  there  is  a  slight  risk  of  purchasing 
tubercular  animals.  On  the  contrary,  he  must  regard  every  animal 
as  tubercular  until  the  contrary  is  proven.  This  will  become  all  the 
more  necessary  as  the  use  of  the  tuberculin  test  increases.  Well-bred 
animals  are  particularly  liable  to  show  tuberculosis  on  the  test.  The 
herds  from  which  they  come  have  been  built  up  by  many  purchases 
from  far  and  wide,  with  no  precautions,  which  assures  the  introduction 
of  tuberculosis.  An  animal  purchased  on  the  test  should  preferably  be 
isolated  for  three  months,  and  then  be  tested  again  before  exposing 
the  clean  herd  to  possible  infection.  As  previously  explained,  one 
test  can  not  be  implicitly  relied  upon. 

The  most  common  method  of  introducing  tuberculosis  is  probably  by 
the  purchase  of  diseased  animals.  Next  to  " buying  in"  the  disease,  the 
feeding  of  raw  skim  milk  from  the  creameries  is  to  be  blamed.  Do  not 
feed  skim  milk  that  comes  from  another  herd  to  calves  without  first 
sterilizing  it.  Prevention  is  simple.  The  disease  is  produced  by  tuber- 
culosis germs,  and  if  we  keep  the  bacteria  away  from  the  cattle  they 
can  not  possibly  develop  tuberculosis.  Although,  experimentally,  cattle 
can  sometimes  be  infected  by  injecting  the  virus  from  tuberculous 
human  beings,  it  is  a  question  if  infection  ever  takes  place  naturally. 

Vaccination,  or  the  immunization  of  cattle  against  tuberculosis,  is 
now  being  advocated  by  some  scientists.  The  methods  are  as  yet  in  the 
experimental  stage,  and  the  effectiveness  of  vaccination  can  not  be 
predicted  at  this  time.  The  California  station  is  testing  the  von  Behr- 
ing  method  on  a  number  of  calves.  The  results  of  these  tests  will  be 
published  later. 


APPLICATION  FOR  TUBLRCULIN. 


To  the  Director  of  the  Agricultural  Experiment  Station,  University  of 

California,  Berkeley. 
Sir: 

Application  is  hereby  made  for doses  of  tuberculin,  to 

be  used  within  thirty  days,  for  testing head  of  mature 

animals  and head  of  young  stock  at ,  and 

belonging  to  me. 

I  agree  that  in  case  any  tuberculous  animals  are  found  in  the  herd- 
to  remove  them  at  once  from  the  healthy  portion  of  the  herd,  so  as  to 
prevent  further  spread  of  the  disease,  and  not  to  sell  them  to  any 
person  except  for  immediate  slaughter. 

I  agree  that  in  case  tubercular  animals  are  found  in  the  herd,  to 
thoroughly  disinfect  the  stable,  and  agree  not  to  add  new  animals  to 
the  herd  until  they  have  been  proven  free  from  tuberculosis  by  the 
tuberculin  test. 

My  express  address  is 

Mail  address,    

Owner. 


APPLICATION  FOR  TUBLRCULIN. 


To  the  Director  of  the  Agricultural  Experiment  Station,   University 

of  California,  Berkeley. 
Sir: 

Application  is  hereby  made  for doses  of  tuberculin,  to 

be  used  within  thirty  days,  for  testing head  of  mature 

animals  and head  of  young  stock  at ,  and 

belonging  to  me. 

I  agree  that  in  case  any  tuberculous  animals  are  found  in  the  herd, 
to  remove  them  at  once  from  the  healthy  portion  of  the  herd,  so  as  to 
prevent  further  spread  of  the  disease,  and  not  to  sell  them  to  any 
person  except  for  immediate  slaughter. 

I  agree  that  in  case  tubercular  animals  are  found  in  the  herd,  to 
thoroughly  disinfect  the  stable,  and  agree  not  to  add  new  animals  to 
the  herd  until  they  have  been  proven  free  from  tuberculosis  by  the 
tuberculin  test. 

My   express   address    is 

Mail  address,   

Owner. 


